see the number "343" on the helmet? it represents the number of firefighters who died on 9/11. >> i was one of the lucky ones that was not killed that day, but i lost many of my friends. >> while the kids were working on the mural, captain berkman would come and visit. she helped them understand what happened that day. >> i didn't know anything about 9/11 at the beginning of this, and i've learned so much. >> and i love seeing people come and see what we did! >> it makes me, like, proud, 'cause, like, all the work that we -- all of us -- done -- it's, like, really special to some people. >> unfortunately, my brother was one of the firemen who passed away, so that's my personal connection. it's very fulfilling to see his memory honored in a place such as this. >> in fact, the students took special care to honor all those who lost their lives in the attacks. >> and we put every single name, 3,000 names, on the wall. >> and every name helps to make sure that we never forget.